比較:JAVA解析XML的四種方法
XML現(xiàn)在已經(jīng)成為一種通用的數(shù)據(jù)交換格式,它的平臺無關(guān)性,語言無關(guān)性,系統(tǒng)無關(guān)性,給數(shù)據(jù)集成與交互帶來了極大的方便。對于XML本身的語法知識與技術(shù)細節(jié),需要閱讀相關(guān)的技術(shù)文獻,這里面包括的內(nèi)容有DOM(Document Object Model),DTD(Document Type Definition),SAX(Simple API for XML),XSD(Xml Schema Definition),XSLT(Extensible Stylesheet Language Transformations),
XML在不同的語言里解析方式都是一樣的,只不過實現(xiàn)的語法不同而已。基本的解析方式有兩種,一種叫SAX,另一種叫DOM。SAX是基于事件流的解析,DOM是基于XML文檔樹結(jié)構(gòu)的解析。假設(shè)我們XML的內(nèi)容和結(jié)構(gòu)如下:
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- <?xml version=”1.0″ encoding=”UTF-8″?> <employees>
- <employee>
- <name>ddviplinux</name>
- <sex>m</sex>
- <age>30</age>
- </employee>
- </employees>
- <?xml version=”1.0″ encoding=”UTF-8″?> <employees>
- <employee>
- <name>ddviplinux</name>
- <sex>m</sex>
- <age>30</age>
- </employee>
- </employees>
本文使用JAVA語言來實現(xiàn)DOM與SAX的XML文檔生成與解析。
首先定義一個操作XML文檔的接口XmlDocument 它定義了XML文檔的建立與解析的接口。
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- package com.alisoft.facepay.framework.bean;
- /**
- *
- * @author hongliang.dinghl
- * 定義XML文檔建立與解析的接口
- */
- public interface XmlDocument {
- /**
- * 建立XML文檔
- * @param fileName 文件全路徑名稱
- */
- public void createXml(String fileName);
- /**
- * 解析XML文檔
- * @param fileName 文件全路徑名稱
- */
- 18.public void parserXml(String fileName);
- 19.}
- 20.package com.alisoft.facepay.framework.bean;
- 21./**
- 22. *
- 23. * @author hongliang.dinghl
- * 定義XML文檔建立與解析的接口
- */
- public interface XmlDocument {
- /**
- * 建立XML文檔
- * @param fileName 文件全路徑名稱
- */
- public void createXml(String fileName);
- /**
- * 解析XML文檔
- * @param fileName 文件全路徑名稱
- */
- public void parserXml(String fileName);
- }
1. DOM生成和解析XML文檔
為 XML 文檔的已解析版本定義了一組接口。解析器讀入整個文檔,然后構(gòu)建一個駐留內(nèi)存的樹結(jié)構(gòu),然后代碼就可以使用 DOM 接口來操作這個樹結(jié)構(gòu)。優(yōu)點:整個文檔樹在內(nèi)存中,便于操作;支持刪除、修改、重新排列等多種功能;缺點:將整個文檔調(diào)入內(nèi)存(包括無用的節(jié)點),浪費時間和空間;使用場合:一旦解析了文檔還需多次訪問這些數(shù)據(jù);硬件資源充足(內(nèi)存、CPU)。
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- package com.alisoft.facepay.framework.bean;
- import java.io.FileInputStream;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.PrintWriter;
- import javax.xml.parsers.DocumentBuilder;
- import javax.xml.parsers.DocumentBuilderFactory;
- import javax.xml.parsers.ParserConfigurationException;
- import javax.xml.transform.OutputKeys;
- import javax.xml.transform.Transformer;
- import javax.xml.transform.TransformerConfigurationException;
- import javax.xml.transform.TransformerException;
- import javax.xml.transform.TransformerFactory;
- import javax.xml.transform.dom.DOMSource;
- import javax.xml.transform.stream.StreamResult;
- import org.w3c.dom.Document;
- import org.w3c.dom.Element;
- import org.w3c.dom.Node;
- import org.w3c.dom.NodeList;
- import org.xml.sax.SAXException;
- /**
- * @author hongliang.dinghl
- * DOM生成與解析XML文檔
- */
- public class DomDemo implements XmlDocument {
- private Document document;
- private String fileName;
- public void init() {
- try {
- DocumentBuilderFactory factory = DocumentBuilderFactory
- .newInstance();
- DocumentBuilder builder = factory.newDocumentBuilder();
- this.document = builder.newDocument();
- } catch (ParserConfigurationException e) {
- System.out.println(e.getMessage());
- }
- }
- public void createXml(String fileName) {
- Element root = this.document.createElement(“employees”);
- this.document.appendChild(root);
- Element employee = this.document.createElement(“employee”);
- Element name = this.document.createElement(“name”);
- name.appendChild(this.document.createTextNode(“丁宏亮“));
- employee.appendChild(name);
- Element sex = this.document.createElement(“sex”);
- sex.appendChild(this.document.createTextNode(“m”));
- employee.appendChild(sex);
- Element age = this.document.createElement(“age”);
- age.appendChild(this.document.createTextNode(“30″));
- employee.appendChild(age);
- root.appendChild(employee);
- TransformerFactory tf = TransformerFactory.newInstance();
- try {
- Transformer transformer = tf.newTransformer();
- DOMSource source = new DOMSource(document);
- transformer.setOutputProperty(OutputKeys.ENCODING, “gb2312″);
- transformer.setOutputProperty(OutputKeys.INDENT, “yes”);
- PrintWriter pw = new PrintWriter(new FileOutputStream(fileName));
- StreamResult result = new StreamResult(pw);
- transformer.transform(source, result);
- System.out.println(“生成XML文件成功!”);
- } catch (TransformerConfigurationException e) {
- System.out.println(e.getMessage());
- } catch (IllegalArgumentException e) {
- System.out.println(e.getMessage());
- } catch (FileNotFoundException e) {
- System.out.println(e.getMessage());
- } catch (TransformerException e) {
- System.out.println(e.getMessage());
- }
- }
- public void parserXml(String fileName) {
- try {
- DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
- DocumentBuilder db = dbf.newDocumentBuilder();
- Document document = db.parse(fileName);
- NodeList employees = document.getChildNodes();
- for (int i = 0; i < employees.getLength(); i++) {
- Node employee = employees.item(i);
- NodeList employeeInfo = employee.getChildNodes();
- for (int j = 0; j < employeeInfo.getLength(); j++) {
- Node node = employeeInfo.item(j);
- NodeList employeeMeta = node.getChildNodes();
- for (int k = 0; k < employeeMeta.getLength(); k++) {
- System.out.println(employeeMeta.item(k).getNodeName()
- + “:” + employeeMeta.item(k).getTextContent());
- }
- }
- }
- System.out.println(“解析完畢“);
- } catch (FileNotFoundException e) {
- System.out.println(e.getMessage());
- } catch (ParserConfigurationException e) {
- System.out.println(e.getMessage());
- } catch (SAXException e) {
- System.out.println(e.getMessage());
- } catch (IOException e) {
- System.out.println(e.getMessage());
- }
- }
- }
#p#
2. SAX生成和解析XML文檔
為解決DOM的問題,出現(xiàn)了SAX。SAX ,事件驅(qū)動。當解析器發(fā)現(xiàn)元素開始、元素結(jié)束、文本、文檔的開始或結(jié)束等時,發(fā)送事件,程序員編寫響應(yīng)這些事件的代碼,保存數(shù)據(jù)。優(yōu)點:不用事先調(diào)入整個文檔,占用資源少;SAX解析器代碼比DOM解析器代碼小,適于Applet,下載。缺點:不是持久的;事件過后,若沒保存數(shù)據(jù),那么數(shù)據(jù)就丟了;無狀態(tài)性;從事件中只能得到文本,但不知該文本屬于哪個元素;使用場合:Applet;只需XML文檔的少量內(nèi)容,很少回頭訪問;機器內(nèi)存少;
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- package com.alisoft.facepay.framework.bean;
- import java.io.FileInputStream;
- import java.io.FileNotFoundException;
- import java.io.IOException;
- import java.io.InputStream;
- import javax.xml.parsers.ParserConfigurationException;
- import javax.xml.parsers.SAXParser;
- import javax.xml.parsers.SAXParserFactory;
- import org.xml.sax.Attributes;
- import org.xml.sax.SAXException;
- import org.xml.sax.helpers.DefaultHandler;
- /**
- * @author hongliang.dinghl
- * SAX文檔解析
- */
- public class SaxDemo implements XmlDocument {
- public void createXml(String fileName) {
- System.out.println(“<<”+filename+“>>”);
- }
- public void parserXml(String fileName) {
- SAXParserFactory saxfac = SAXParserFactory.newInstance();
- try {
- SAXParser saxparser = saxfac.newSAXParser();
- InputStream is = new FileInputStream(fileName);
- saxparser.parse(is, new MySAXHandler());
- } catch (ParserConfigurationException e) {
- e.printStackTrace();
- } catch (SAXException e) {
- e.printStackTrace();
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- }
- class MySAXHandler extends DefaultHandler {
- boolean hasAttribute = false;
- Attributes attributes = null;
- public void startDocument() throws SAXException {
- System.out.println(“文檔開始打印了“);
- }
- public void endDocument() throws SAXException {
- System.out.println(“文檔打印結(jié)束了“);
- }
- public void startElement(String uri, String localName, String qName,
- Attributes attributes) throws SAXException {
- if (qName.equals(“employees”)) {
- return;
- }
- if (qName.equals(“employee”)) {
- System.out.println(qName);
- }
- if (attributes.getLength() > 0) {
- this.attributes = attributes;
- this.hasAttribute = true;
- }
- }
- public void endElement(String uri, String localName, String qName)
- throws SAXException {
- if (hasAttribute && (attributes != null)) {
- for (int i = 0; i < attributes.getLength(); i++) {
- System.out.println(attributes.getQName(0)
- + attributes.getValue(0));
- }
- }
- }
- public void characters(char[] ch, int start, int length)
- throws SAXException {
- System.out.println(new String(ch, start, length));
- }
- }
#p#
3. DOM4J生成和解析XML文檔
DOM4J 是一個非常非常優(yōu)秀的Java XML API,具有性能優(yōu)異、功能強大和極端易用使用的特點,同時它也是一個開放源代碼的軟件。如今你可以看到越來越多的 Java 軟件都在使用 DOM4J 來讀寫 XML,特別值得一提的是連 Sun 的 JAXM 也在用 DOM4J。
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- package com.alisoft.facepay.framework.bean;
- import java.io.File;
- import java.io.FileWriter;
- import java.io.IOException;
- import java.io.Writer;
- import java.util.Iterator;
- import org.dom4j.Document;
- import org.dom4j.DocumentException;
- import org.dom4j.DocumentHelper;
- import org.dom4j.Element;
- import org.dom4j.io.SAXReader;
- import org.dom4j.io.XMLWriter;
- /**
- * @author hongliang.dinghl
- * Dom4j 生成XML文檔與解析XML文檔
- */
- public class Dom4jDemo implements XmlDocument {
- public void createXml(String fileName) {
- Document document = DocumentHelper.createDocument();
- Element employees=document.addElement(“employees”);
- Element employee=employees.addElement(“employee”);
- Element name= employee.addElement(“name”);
- name.setText(“ddvip”);
- Element sex=employee.addElement(“sex”);
- sex.setText(“m”);
- Element age=employee.addElement(“age”);
- age.setText(“29″);
- try {
- Writer fileWriter=new FileWriter(fileName);
- XMLWriter xmlWriter=new XMLWriter(fileWriter);
- xmlWriter.write(document);
- xmlWriter.close();
- } catch (IOException e) {
- System.out.println(e.getMessage());
- }
- }
- public void parserXml(String fileName) {
- File inputXml=new File(fileName);
- SAXReader saxReader = new SAXReader();
- try {
- Document document = saxReader.read(inputXml);
- Element employees=document.getRootElement();
- for(Iterator i = employees.elementIterator(); i.hasNext();){
- Element employee = (Element) i.next();
- for(Iterator j = employee.elementIterator(); j.hasNext();){
- Element node=(Element) j.next();
- System.out.println(node.getName()+“:”+node.getText());
- }
- }
- } catch (DocumentException e) {
- System.out.println(e.getMessage());
- }
- System.out.println(“dom4j parserXml”);
- }
- }
#p#
4. JDOM生成和解析XML
為減少DOM、SAX的編碼量,出現(xiàn)了JDOM;優(yōu)點:20-80原則,極大減少了代碼量。使用場合:要實現(xiàn)的功能簡單,如解析、創(chuàng)建等,但在底層,JDOM還是使用SAX(最常用)、DOM、Xanan文檔。
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- package com.alisoft.facepay.framework.bean;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.util.List;
- import org.jdom.Document;
- import org.jdom.Element;
- import org.jdom.JDOMException;
- import org.jdom.input.SAXBuilder;
- import org.jdom.output.XMLOutputter;
- /**
- * @author hongliang.dinghl
- * JDOM 生成與解析XML文檔
- */
- public class JDomDemo implements XmlDocument {
- public void createXml(String fileName) {
- Document document;
- Element root;
- root=new Element(“employees”);
- document=new Document(root);
- Element employee=new Element(“employee”);
- root.addContent(employee);
- Element name=new Element(“name”);
- name.setText(“ddvip”);
- employee.addContent(name);
- Element sex=new Element(“sex”);
- sex.setText(“m”);
- employee.addContent(sex);
- Element age=new Element(“age”);
- age.setText(“23″);
- employee.addContent(age);
- XMLOutputter XMLOut = new XMLOutputter();
- try {
- XMLOut.output(document, new FileOutputStream(fileName));
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- public void parserXml(String fileName) {
- SAXBuilder builder=new SAXBuilder(false);
- try {
- Document document=builder.build(fileName);
- Element employees=document.getRootElement();
- List employeeList=employees.getChildren(“employee”);
- for(int i=0;i<employeeList.size();i++){
- Element employee=(Element)employeeList.get(i);
- List employeeInfo=employee.getChildren();
- for(int j=0;j<employeeInfo.size();j++){
- System.out.println(((Element)employeeInfo.get(j)).getName()+“:”+
- ((Element)employeeInfo.get(j)).getValue());
- }
- }
- } catch (JDOMException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- }
希望對你有幫助。
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